Sealing piston ring



Nv. 1T, v93 lc. L. Ll-:wls EI'IALl '1,731,183

SEALING PIsToN RING Filed April 19, 1928 2 sheets-sheet 1 Nov. l1, 1930. c. L.. Lr-:wls El' AL 1,731,183

SEALING PIsToN RING 3 Filed April 19, 1928 2 Sheets-Sheet 2 nas/776A? N Patented Nov.` l1, `1930 UNITED oFFlcrs.A

CHESTER L. LEwIs AND HARRY opsErrEnpEa "por" `1 v,.' 1tri;.'a1-rn.A oEEeoN s EALING rIs'reit-BI e Application led April 19,

vOur invention. has :for its object the preventing of undue wear of the cylinder Walls and pistbny rings of engines, and similar de vices. y f 5' We have discovered that undue wear of the walls'of the cylinder, and the piston rings y on the cylinder walls.

As is well known, the spring inherent in the metal of which the piston rings are usually constructed generally'represents a pressure .of about six to eight pounds per s uare inch, but with the gas pressures intro uced behind the piston ringthese ressures not infrequently climby to six hun red pounds per, square inch,` in internal combustion engines; hence, the undue wear unavoidably resulting with such enormous. pressures. And, of course, when the cylinder walls or the piston rings are once worn to such extent that the gas pressures are no'lon er confined to the top of the piston, the englne no longer functions efficiently; and, besides, the gases pass-l ing by the piston rin tend to break down the lubricating oil, an in that way'augment the undue wear. y The common piston ring itself cannot be ar# ranged so as to bar the entrance of the 'gaspressures behind it; for no matter how neatly the piston ring is'tted in its groove, some fractional space must be allowed between the top surface of the piston ring and the opposed 4 35 surface of the groove of the piston, so as to permit the piston l,ring some relative transverse motion in its groove. And it is through such minute assage-way that the gas vpressures enterbelhind the piston ring, and Wear 49 on these minute passage-ways is especially severe on the first or upper piston ring, with the result that the rin and groove wear rapidly and the ring quic y becomes very loose in its grooves. We are aware that attempts have heretofore been made to exclude the pressure from behind the vpiston ring, but the means employed of which we have any knowledge failed, and were incapable of producing the result intended.

. ton ring, and, at the same time, the interior ipleriphery of the sealing ring will be held in rm Contact with the inner longitudinal wall of the groove in which the piston ring is located. Thus the high gas pressures occurring in the cylinder serve to hold the sealing ring in position for closing substantially the passage-ways from the cylinder intothe space behind the piston ring. Since it is'impossible, in practice, to effect the entire exclu'- sion of the pressure from behind the piston'V rings,-means must be rovided to relieve such pressure as may be set u there, by leakage; such means to be ada te to permit the presy sure to escape from ehind thevpistonring into the body of the cylinder below the piston ring, thus into larger space.

Our invention ma be applied to the pisi tons of all types o reciprocating engines, by simply enlarging thegroove of the piston ring longitudinally or narrowing the piston ring to accommodate the sealing ring.

Where it is preferred to employ a deep piston ring and a correspondingly deep sealing ring, thev head of the piston must be made with a removable section so as to permit 'the insertion of such deep rings."v

Relief ofthe pressure behind the piston ring, due to leakage past the sealing ring, may be accomplished by providing the piston rin with la suitable scarf as hereinafter descri ed; or by providing the space behind the piston ring with a valve controlled vent.

The details of our invention are hereinafter fully described with reference to 'the accompanying drawings.

In such drawings:

. Fig. 1 shows a central longitudinal section of a piston and its cylinder illustrating the relative arrangement and proportions of the sealing and piston rings;

provided i of the pressure from piston ring.

Figs. 2, 3, 4 and '5 show fragmentary sections of a piston and illustrate modifications of the sealing ring and the groove therefor.

Fig. 6 shows in a section taken on the line 6-6 of Fig. 1, the relative osition of the sealing and piston rings in t e groove and the wall of the cylinder, and illustrates the means provided for sealing the contiguous ends ofthe piston ring;

Fig. 7 shows fragmentary views illustrating the arrangement. of a scarf element of the piston-ring, adapted t'o prevent substantially the passage of pressure back to the underside of the sealingy ring, but permittingthe escape behind the piston ring down into the body of the cylinder;

Fig. 8 shows similar details of another type of scarf for the piston ring;

Figs. 9 and 10 show modifications of a piston adapted for piston and sealing ring of relatively greater of the piston is made removable;

Fig. 11 shows a furthermodification adapted for reciprocating pistons, in which the pressure is 'continuous rather than momentary.

Fig. 12 shows a detail of one of the valve -discs employed in the combination illustrated by Fig. 11.

Referring now to Figures 1 to 7' inclusive, a piston ais provided, ofthe usual form, and with a number of circumferential grooves 6,6', b2 and b3. The piston 1s ar,- ranged in its cylinder c and the grooves are also of the usual form except that the groove b is of the same depth. but somewhat wider than the other grooves. Piston rings d, d', d2 and da are arranged in the grooves.

A sealing ring e is mounted in the groove b bearing on and overlying the ring d. The

sealing ring e is circular and relatively thin but of approximately the same width as the The circumferential edge of the piston wall above as to expose -a portion of the circumferential rim of the sealing ring to the pressure, and the lsealing ring-has a sliding fit in the groove -Zi on the piston ring thereby providing a space between the top face of the sealingringand opposed to the wall surface of the piston in whichthe pressure can enter to bear thev sealing ring firmly down on the piston ring.

The sealin ring is split as at f, Fig. 6, to pei'.- mit it to e sprung'open suiciently to be snapped into the groove b in a manner similar to the way the piston rings are mounted in their grooves. The sealing ring is adapted, however, to bear firmly against the inner wall of the roove b and its outer circumfer ential edge oes no t touch the wall of the cylinder so as to leave a space for the pressure to bear against the outer edge of the sealing ring and hold the same firmly, and in gas tight relation, -against the inner wall of the' groove b..

depth vin which the head the groove b is beveled sov In Figure '9 is shown a modification of our invention adapted for pistons provided with a wider piston ringhh and corres Aondingly deeper groove z', w ich can not e .sprung sufficiently to be snapped into place. To overcome this, the head j of the piston is made removable and held in place by bolts c. The

construction of the sealing ring Z in4 this i is not split, to be mounted over the piston ring 4. Of course, this modification is also adapted for-a wide piston ring, which can not be sprung sufhciently to be snapped into its` groove, as shown in Fig. 9.

Figs. 11 and 12 show a modification of our invention adapted for high pressureipumps or steam cylinders or other devices in which the pressures of the working fluid is continu-- ous, not momentary, as in' an internal combustion engine. i

AThe piston' 10 in this modification is dou.

ble ended, that is reciprocating, and sealing rings 11 are provided overlying the piston rings 12 on the surfaces adjacent to the rea 95 spective ends of the piston.

Since in this type, the pressure is continuous a small amount of fluid will tend to enter the space behind the piston and force the piston ring outwardly againstthe wall ofthe cylinder. To rovide means to permit this fluid to esca e rom behind the ring aconduit 13 is provi ,ed leading from the groove 14 to a longitudinal conduit-15 opening at each end of the piston. VRecesses 16 and 17 are provided at each end' of the conduit 15 in which are-seated check valves 18 and 19 held in place bycaps 18a and 19a threaded into the said recesses tohold the checkvalves in v place. The pressure ofthe` fluid will thus close the respective valve and the fluid in the conduits may escape through thel other valve against which there'is relatively less pressure.

In order to insure that the pressure of the impelling fluid will bind the sealing i ring tightly and closely against the piston-ring and the inner wall of its groove to prevent the fiuid from passing behind the piston ring,we have shown in Figures 1,3, ff and 5 respectively supplementary means provided to assist the pressure of the fluid to act upon the sealing ring. In Fig. 1 the upper' edge of the groove b is beveled asat a, thus exposing a portion of the surface of the ring to the direct pressure of the fluid.` In Fig. 3, the head 2O of the piston is constructed of slightly less diameter than the body of the piston 21 thus exposing not only a portion of y the upper surface,- of the sealing ring e, but

also permitting the fluid to bear against the periphery of the ring. Fig. 4 shows a sealing ring e beveled as at e2, the head of the piston also bein of slightly less diameter f than -its body. ig. 5 shows a form similar more closely the tongue 21al will bind in the groove 22a and by arranging the tongue and groove on the surface of the ring adjacent, the head of the piston and since the pressure I is downward, the-fluid to pass behind the contiguous ends, must pass between the said tongue and groove and consequently be subit must betaken care of; that is, allowedto stantially hindered.

At the Sametime since some leakage of pressurebehind the piston ring will occur,

escape into the body of the cylinder. To this end, by the arrangement of the scarf of the piston ring shown in Fig. 7, an opening is provided at 25 through which the pressure can so escape,

Fig. .8 shows a modification of this feature, adapted to permit the piston ring to be mounted in its groove with either of its surfaces uppermost. Av recess 23* formed with a tongue shaped ortion 23b i's provided in the outer surface o the piston ring at the A 'end 23 and a correspondingly complementary shaped recess 24a is provided in the sur- A face of the adjacent end 24, so that when the two ends are together, the end of each ring will fill the recess in the other, sealing the cylinder, the piston ringbeing provided with a scarf preventing substantially the passing of the pressure to the inner side of the piston ring, and means adapted to permit the pressure entering behind the piston ring to escape into the body of the cylinder below the piston ring.

2. In combination, a cylinder and a piston therein provided with a circumferential groove, a piston ring seated infsaid groove,

and asealing ring seated on the pressure side of the piston ring, the sealing r1ng having a lesser diameter than the piston ring, the circumferential edge and the -top ofthe sealing ring being exposed to the pressure in the cylinder, the piston ring being provided with a scarf preventing;substantially the passing of the pressure to the inner side of theJpiston ring, and the scarf of the piston ring being adapted to permit the pressure entering behind the piston ring to escape into the body of the cylinder below the piston ring.

CHESTER L. LEWIS. HARRY O. SETTERBERG.

junction of the two ends against the Huid.

The operation of our improvement will be readily understood, by Vall practical in .the art, from the description above given.

By constructing the contiguous ends of the piston ring, Huid is also revented from working through any space ends; y

Furthermore sealin rings may be provided in thel second piston ring grooves or all of them, if desirable, which might be the case in Diesel engines, as the wear on the piston rings in this type is especially severe.

We claim:

1. In combination, a cylinder and a piston therein provided with a circumferential groove, a piston ring seated insaid groove,

and a sealingring seated on the pressure side of the piston ring, the sealing ringhaving lesser diameter than the piston ring, the cirtween the two cumferential edge and the top of the sealing i ring being exposed to the pressure in the 

